The present invention relates to portable heaters and more particularly to compact heaters or warmers to be carried on the person for circulating heat in wearing apparel such as gloves or boots. Many prior heating systems for this purpose are known in the art. Most notably, I am an inventor in each of the following four prior patents, all of which disclose such portable heating systems: U.S. Pat. Nos. 4,180,922; 4,281,418; 4,334,519; and 4,441,483. The entire disclosure of each of the above cited patents is hereby incorporated herein and made a part hereof by reference.
Other prior art patents known to me which are pertinent to heaters or warming apparatus for wearing apparel include the following. U.S. Pat. No. 2,648,325 discloses a jacket equipped to impart heat to the body of a wearer by including self-contained means for generating heat which comprises a warm liquid circulating system means that is actuated by breathing of the jacket wearer to cause circulation of the liquid through a network of conduits. The apparatus of this patent includes a heater such as a catalytic or chemical heater. The patent also discloses bulbs which form a part of the liquid circulation system and which may be alternately compressed and released to enhance flow of liquid in the system.
U.S. Pat. No. 3,000,616 discloses an air charged body warmer in which periodic collapse of one or more bladder-like members cooperates with a system of check valves to produce circulation through a closed conduit system in conjunction with normal working or running activities.
U.S. Pat. No. 912,527 discloses a portable foot and body warmer wherein a lamp chamber contains a heater element which heats fluid that flows through a combined pump and heat exchange unit.
U.S. Pat. No. 3,712,288 discloses a hand warmer glove with a bladder pump which is separate from the warming element and which pump is utilized to extract or draw heated air from around the heater element for delivery thereof throughout the glove to warm the hand and fingers.
There are, of course, a great many additional prior art references which disclose conventional hand warmers or other portable furnace devices, as well as such devices in combination with various garments such as vests, body suits, boots and shoes, mittens, bicycle handgrips, body wraps, and the like.